CGT calculation gifted property sold

My wife was gifted a property by her parents on a 50% share with her sister in 2003. Market value at that time approx £150K. The house was sold when the mother was left on her own in 2016 for £185K. At the same time a new property was purchased in the name of my wife for £174K. The mother has now left the property and my wife has sold the property for £257K. Profit to share with sister. Is CGT only calculated over the last property or do we need to go back to 2003? Thanks for your advise. Eric

Hi,
There are 2 different gains to be reported here as there is the one for 2016 if your wife did not live in the property, then the gain for the property bought in 2016 and now sold.
Thank you.